First lay the fish in your hand with its head toward your palm and the tail toward your fingers. Hold the dorsal spine between your middle and ring finger so the fish is belly up and you won't get stuck (Which by the way, hurts like crazy!). The genital pore is in a small furrow of tissue (in healthy fish) and will be obstructed by the pelvic fins. Pull down on the tail gently to arch the fishes spine and the pelvic fins will stand and the furrow open to display the genital pore and the anus of the fish. The male has a somewhat ridged genital papillae on which the spermatoduct is on the back side, facing the tail fin. A gravid female will also show an extended papillae but the oviduct is on the ventral side of the papillae (And may also show a little redness if really gravid). A thin or emaciated female will have just two pink pores, the oviduct and the anus.